Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, United States.
Med Eng Phys. 2010 Dec;32(10):1224-8. doi: 10.1016/j.medengphy.2010.08.015. Epub 2010 Sep 26.
The valid application of accelerometry and interpretation of its output (i.e., counts per unit time) for the measurement of walking behavior in persons with multiple sclerosis (MS) rests upon multiple untested assumptions. This study tested the assumption that a waist-worn accelerometer should capture the intra- and inter-person variation in walking behavior. Twenty-four participants with a neurologist-confirmed diagnosis of MS and who were ambulatory with minimal assistance undertook three 6-min periods of over-ground walking that involved comfortable (CWS) and then slower (SWS) and faster (FWS) walking speeds while wearing ActiGraph, model 7164, accelerometers around the waist and ankle. The experimental manipulation of walking was successful such that the CWS was 76.7±13.0m/min (range=55.6-105.14), whereas the SWS and FWS were 64.3±12.3m/min (range=44.5-90.1) and 89.1±13.8m/min (range=60.9-116.4), respectively. Movement counts from the waist and ankle-worn accelerometer were strongly associated with the manipulation of speed, but the association was stronger for the waist than ankle based on both eta-squared estimates (η(2) values=.78 and .46) and the average squared multiple correlations from individual regression analyses (R(2) values=.97±.04 and .88±.21). The bivariate correlation between movement counts from the waist-worn accelerometer and speed of walking (r=.823, p=.001) was large in magnitude and significantly different (z=3.22, p=.001) from that between movement counts from the ankle-worn unit and walking speed (r=.549, p=.001). This study provides novel evidence that an accelerometer worn around the waist captures intra- and inter-person variation in over-ground walking behavior in those with MS.
加速度计的有效应用及其输出（即单位时间内的计数）在测量多发性硬化症（MS）患者的行走行为方面，基于多个未经测试的假设。本研究检验了这样一个假设，即腰部佩戴的加速度计应该能够捕捉到个体内和个体间行走行为的变化。24 名参与者经神经科医生确诊为 MS，在最小辅助下能够行走，他们在佩戴 ActiGraph 模型 7164 腰部和脚踝加速度计的情况下，进行了三次 6 分钟的地面行走，包括舒适（CWS）、较慢（SWS）和较快（FWS）行走速度。行走的实验操作是成功的，CWS 的速度为 76.7±13.0m/min（范围=55.6-105.14），而 SWS 和 FWS 的速度分别为 64.3±12.3m/min（范围=44.5-90.1）和 89.1±13.8m/min（范围=60.9-116.4）。腰部和脚踝佩戴的加速度计的运动计数与速度的操纵密切相关，但基于 eta-平方估计值（η（2）值=.78 和.46）和个体回归分析的平均平方多重相关系数（R（2）值=.97±.04 和.88±.21），腰部的相关性比脚踝更强。腰部佩戴的加速度计的运动计数与行走速度之间的双变量相关性（r=.823，p=.001）具有较大的相关性，且显著不同于脚踝佩戴单元的运动计数与行走速度之间的相关性（r=.549，p=.001）（z=3.22，p=.001）。本研究提供了新的证据，表明腰部佩戴的加速度计可以捕捉到 MS 患者在地面行走行为中的个体内和个体间变化。
